Tinker gets old emails? (8)
I believe the answer is:
messages
'emails?' is the definition.
(email is a type of message)
'tinker gets old' is the wordplay.
'tinker' becomes 'mess' (to tinker with something is to mess with it).
'gets old' becomes 'ages' ('age' can be a synonym of 'get old').
'mess'+'ages'='MESSAGES'
(Other definitions for messages that I've seen before include "Shopping up north" , "Communications, written, spoken or signaled" , "Notes" , "Communications or errands" , "Communications from one person to another" .)